Topside Power Sports Winterized incorrectly. Freeze plugs pushed out of Mercruiser louisville Tennessee

I brought my boat to this company for winyerization in the fall of 2013 due to the deal i got with them the year before.  $75 for winterization isnt bad.  I picked up the boat after their service and covered it for the winter.  Spring rolls around, friday of memorial day weekend,  and i went to clean behind the seats to find a brass freeze plug or core plug as theyre called, sitting on my engine mount as if it had just fallen oit of the engine.  I checked the other side of the engine (both in front) and sure enough, it was out as well.  Anyone who knows boata knows tjat this ia caused by water being left in the engine during the winter.  Once it freezes the plugs are pushed out.  I brought the boat back to Topside Powersportasand was told it would be taken care of.  its been over a month and they still have not touched it.  Every week i am assured that "next week" it will be ready.  This isnt just maintenance to be done.  We're talking about damage due to negligence.  Not my negligence but the negligence of the individuals who winterized my boat.